1. Field of the Invention
The present invention relates to an image display device using a multi-window system in which a plurality of images can be displayed simultaneously on regions or regions of a display.
2. Description of the Related Art
Recently, image display devices, which adopt a multi-window system for displaying images on specified regions of a screen called windows, have been widely used.
The image display devices are able to execute a plurality of application programs simultaneously and selectively display the application programs or execution results thereof on different windows. A case where the input and output application programs are displayed on windows overlapping each other, will be described with reference to FIG. 5. As shown in FIG. 5, part of a display window 1 on which an image is to be displayed is partly shielded from a window 2. Regions (A) and (B) of image data corresponding to regions (1) and (2) of the window 1 which are not shielded from the window 2, are detected, and data of the regions (A) and (B) are transferred to their corresponding regions (1) and (2), respectively, with a result that the images in the regions (A)and (B) are displayed on the window 1.
In such an image display device, there is a case where original image data is displayed on a window as an enlarged or reduced image. In this case, the enlargement or reduction processing is executed when data is transferred as described above.
Since the enlargement or reduction processing is generally executed independently for each data of the regions (A)and (B), images of the regions (1) and (2) corresponding to the regions (A) and (B)are shifted from each other between these regions by an error in the enlargement or reduction processing.
More specifically, when the image data differs in size from the window on which the image is to be displayed, in other words, when the regions (A) and (B) of the image data differ in size from the regions (1) and (2) of the window 1, respectively, the enlargement or reduction processing is executed independently for each of the regions (A) and (B). Even though the seeming magnifications of enlargement or reduction of the two regions (A) and (B) are the same, a slight difference occurs between the magnifications since the conditions for omitting the decimals of the magnifications are different. Therefore, the images of the regions (1) and (2) are shifted from each other after the enlargement or reduction processing is executed.